A new VO-MoO-TiO-SO nanostructured aerogel catalyst for diesel DeNO technology

A new V 2 O 5 -MoO 3 -TiO 2 -SO 4 2− nanostructured aerogel system, containing V and Mo loadings representative of the V 2 O 5 -MoO 3 /TiO 2 commercial SCR catalyst, was developed via a one step sol-gel method combined with the supercritical drying approach for the low temperature selective catalytic reduction of NO by NH 3 , in excess O 2 . The new V 2 O 5 -MoO 3 -TiO 2 -SO 4 2− catalyst was analysed via XRD, N 2 -physisorption, H 2 -TPR, NH 3 -TPD, Raman spectroscopy, XPS and DR UV-vis spectroscopy. The elaboration and characterization of TiO 2 , V 2 O 5 -TiO 2 , MoO 3 -TiO 2 , V 2 O 5 -MoO 3 -TiO 2 , TiO 2 -SO 4 2− , V 2 O 5 -TiO 2 -SO 4 2− and MoO 3 -TiO 2 -SO 4 2− aerogel samples were also reported in this work. The results prove the successful synthesis of nanostructured aerogel materials with good crystallinity of the TiO 2 anatase phase, a developed mesoporous texture and a nanometer size as new SCR catalysts. V, Mo and SO 4 2− were found to be highly dispersed on the TiO 2 surface, and their presence and the diverse interactions developed between them strongly affect the physicochemical properties and catalytic behaviour of the derived sol-gel powders. Among all the samples investigated, the new V 2 O 5 -MoO 3 -TiO 2 -SO 4 2− aerogel was found to be the most efficient catalyst for the low temperature NO-SCR: compared to a V 2 O 5 -WO 3 /TiO 2 commercial catalyst (EUROCAT), it demonstrates similar SCR activity in the 200-375 °C temperature range, but, at higher temperatures (375-500 °C), it exhibits superior catalytic performance. A complete conversion of NO into N 2 (100%) was achieved in the 450-500 °C temperature range over the new V 2 O 5 -MoO 3 -TiO 2 -SO 4 2− nanostructured aerogel catalyst, when the NH 3 -SCR reaction was realized using 1000 ppm NO and 1000 ppm NH 3 , in the presence of 3.5% H 2 O. A new V 2 O 5 -MoO 3 -TiO 2 -SO 4 2− nanostructured aerogel catalyst exhibits superior SCR activity compared to the V 2 O 5 -WO 3 /TiO 2 commercial catalyst (EUROCAT) at high temperatures (375-500 °C).